The invention is suitable for transport units which comprise coils of container blanks which in a filled state form flexible containers of a collapsible type.
A container blank is an empty, pre-made container which is supplied to a filling machine in order to produce filled containers.
A container of collapsible type is also referred to as a stand-up pouch, and by a container of collapsible type is thus meant a container with walls of a flexible plastic material, which are flexible and connected to each other to define a compartment, whose volume is dependent on the relative position of the walls. In its unfilled state, the container, and thus its container blank, is flat. The container blanks can be provided in a form of a coil, in which a continuous web of container blanks is wound on a reel.
One example of a container of a collapsible type comprises three wall portions, of which two form opposite side walls and a third forms a bottom wall. The container blanks for this type of containers can be made, for instance, by folding a continuous web of material in the form of an M, after which the wall portions are joined along a connecting portion to define a closed compartment. The container blanks can also be made by joining three continuous webs of material, one of which is folded in the form of a V to form the above-mentioned bottom wall. Regardless of method, this results in a continuous web of container blanks which, seen in the transverse direction of the web, have a first portion with a first number of layers (two walls) and a second portion with a second number of layers (four walls). When winding such a web on a reel, a coil is obtained, which in the first portion has a first density and in the second portion has a second density. This difference in density causes problems in handling, packing and transport of the coils.
Due to the difference in density, the coils cannot be stacked on top of each other without problems of instability and interleaving of the turns of two coils stacked on each other. Such instability and interleaving may cause “upsetting” and damage to the container blanks.
In order to prevent this, the coils may be transported one by one in separate boxes. This results in unnecessary costs and also an environmental problem in the form of unnecessary packing.
Alternatively, the load in form of one or more coils each comprising a web being wound on a reel may be arranged on a pallet type load carrier. An example of such a transport unit is disclosed in WO2008/013486 A1. The transport unit disclosed therein has a load distributing element arranged on top of the load and a tightening strap encloses a force-absorbing structure formed by the load carrier, the reel and the load distributing element and is thus adapted to secure the load to the load carrier. With such a transport unit, the reel of the coil in combination with the load carrier and the load distributing element is used to form a force-absorbing structure. By the load distributing element being arranged on the upper surface of the load, the tightening force applied by the tightening strap will be absorbed by the force-absorbing structure.
The overall cost for this alternative transport unit is considerably lower that the cost involved for transporting coils in separate boxes. However, a further reduced cost would still be favourable.
The load distributing element may be in the form of a wood board, and in some cases the tightening force applied by the tightening strap may cause the wood board to bend, which may cause deformation of the web of coil. Such deformation of the web may cause problems when using the container blanks of the web in a filling machine. More particular, the deformation may hamper opening of a duct of the container blank, through which duct a filling pipe of the filling machine is to be inserted in order to transfer a product to the container blank for producing a filled container.
There is thus a need for an improved type of transport unit.